A conventional vacuum cleaner having a cyclone dust collector is disclosed in Japanese Patent Application Published No. H6-85753. FIG. 8 is a perspective view of this vacuum cleaner. A cleaner body 101 has an electric blower (not shown) housed inside and has a nozzle (not shown) formed so as to face the floor surface. On top of the cleaner body 101, a cyclone dust collector 103 is supported so as to be pivotable back and forth.
FIG. 9 is a front sectional view of the cyclone dust collector 103. FIG. 10 is a sectional view taken along line D—D shown in FIG. 9. As shown in these figures, the cyclone dust collector 103 has a suction pipe 104 and an exhaust pipe 105 formed outside a cylindrical outer cyclone 113 integrally therewith. The outer cyclone 113 is composed of a transparent dust collector section 113b fitted integrally to an inlet section 113c located above it. In the inlet section 113c is formed an inlet port 113a through which air is introduced into the inlet section 113c substantially tangentially thereto from the suction pipe 104.
Between the suction pipe 104 and the exhaust pipe 105, a pipe 106 is arranged. The pipe 106 is fitted with a grip 107 (see FIG. 8) to be gripped by the user. By operating the grip 107, the user can move the vacuum cleaner 100 around smoothly, with casters 111 (see FIG. 8) rolling on the floor surface.
Inside the outer cyclone 113, an inner cyclone 114 having the shape of a truncated cone is arranged with the smaller-diameter end thereof down. The lower end of the inner cyclone 114 is open so as to communicate with a dust collection container 109 that is formed integrally with the outer cyclone 113. At the upper end of the inner cyclone 114, an exhaust section 110 having a circular passage is provided.
Outside the inner cyclone 114, a communicating passage 108 is formed. Through the communicating passage 108 and the exhaust section 110, the outer cyclone 113 and the inner cyclone 114 communicate with each other. At the center of the exhaust section 110, an exhaust port 110a is formed that communicates with the exhaust pipe 105.
In the vacuum cleaner 100 structured as described above, when the electric blower is driven, suction force appears at the nozzle, causing air to be sucked in through the nozzle. The sucked air then passes through the suction pipe 104, and flows into the outer cyclone 113 through the inlet port 113a in the direction indicated by arrow A1. Under centrifugal force, the sucked air is then made into a stream that whirls along the inner wall of the outer cyclone 113 while moving downward. Meanwhile, the sucked air collides with the inner wall of the outer cyclone 113, causing large particles of dust 112a to be separated and collected inside the outer cyclone 113.
Thereafter, the sucked air flows upward along the outer wall of the inner cyclone 114, then flows into the communicating passage 108 in the direction indicated by arrow A2, and then flows through the exhaust section 110 into the inner cyclone 114 in the direction indicated by arrow A3. Under centrifugal force, the sucked air that has flowed into the inner cyclone 114 is then made into a stream that whirls along the inner wall of the inner cyclone 114 while moving downward. Meanwhile, the sucked air collides with the inner wall of the inner cyclone 114, causing fine particles of dust 112b to be separated and collected inside the dust collection container 109.
Then, the sucked air having dust and the like removed therefrom flows upward in a central portion of the inner cyclone 114, and is discharged out of the cyclone dust collector 103 through the exhaust port 110a in the direction indicated by arrow A4. Then, the sucked air flows through the exhaust pipe 105 to the electric blower so as to be discharged out of the vacuum cleaner 100. In this way, dust is collected.
When the dust collector section 113b, which is integral with the dust collection container 109, is pulled out downwardly forward, the inlet section 113c is disengaged from the dust collector section 113b and the inner cyclone 114 is disengaged from the dust collection container 109. This permits the user to dispose of the large particles of dust 112a collected in the outer cyclone 113 and the fine particles of dust 112b collected in the dust collection container 109.
However, in the conventional vacuum cleaner described above, which has an outer cyclone 113 and an inner cyclone 114 provided inside the cyclone dust collector 103, the sucked air is made to flow downward and then upward in each of the outer and inner cyclones 113 and 114. This increases pressure loss, and thus lowers dust collecting performance. The pressure loss can be reduced by providing only one of the outer and inner cyclones 113 and 114, but this results in insufficient removal of fine particles of dust, leading to the clogging of the exhaust port 110a with fine particles of dust.
Moreover, when the dust collector section 113b is pulled out for the disposal of the collected dust and the like, the dust collector section 113b is open at the top. Thus, while the dust collector section 113b is being carried to a place where to dispose of dust, the collected dust is scattered about, degrading the hygiene of the environment and of the user's hands and fingers. Moreover, since dust and the like is collected at two locations, i.e. in the dust collector section 113b and the dust collection container 109, these two components both require cleaning, making their cleaning complicated.